Mayonnaise Packets

Certainly not the most glamorous post, but as economic times get tougher, I notice I'm not the only one storing my lunch in the office fridge. I'm trying to figure out a place to buy packets of mayonnaise so that I can pack them in with my sandwich and not have to have mayonnaise sitting on the bread for five hours. I'm curious if anyone knows any fast food places that just have condiment packages sitting out--that would seem in keeping with my newfound frugality. But I'm also perfectly happy to buy my own packets; I just can't seem to find them anywhere.

(Obviously, I could also just buy my own jar and put it in the fridge, but I don't think the economy has sunk to that level just yet.)